An \(L\) -bisimulation is a relation \(S\)  such that \(S\)  and
\(S^\circ  \)  are \(L\) -simulations. Two states are \(L\) -bisimilar
if there exists an \(L\) -bisimulation relating them.

Marti and Venema [1]} show that if \(L\)  is a lax
extension that preserves diagonals, then \(L\) -bisimilarity coincides
with behavioural equivalence.
